You have a great idea for a nonfiction book. Everybody thinks it’s a great idea. But will a book publishing company think it’s a great idea – enough to pay you an advance, commission you to write it, publish your book and sell it?

That will depend largely on your book proposal. Here’s where you demonstrate persuasively that your idea has merit, and that the company will benefit from publishing your book. Of course, even a solid idea and a great book proposal can’t guarantee success, but they surely can tip the odds in your favor. But if either the idea or the proposal is weak, your chances of a sale are slim to none.

Book editors look for certain things when reviewing book ideas and proposals. To improve your chances of winning a book publisher’s contract, let’s look at the five key questions they ask and the best ways to answer them.

1. Is there a large enough audience interested in this topic to justify publishing a book?

You want to stay away from a highly specialized book, which draws limited audience. You want your book to be among the books that appeal to a general audience or at least to a large segment of the general population.

You must demonstrate to your prospective publishing agent that your large audience – of hundreds of thousands of people, if not millions – exists.

One excellent source of market data is Standard Rate and Data Service(SRDS), a book listing US magazines that accept advertising and their circulations. SRDS is available at your local library or from the publisher (tel. 847/375-5000). Look for the combined circulation of the largest publications in your book’s area.

However, keep in mind that only a small percentage of the intended audience will actually buy your book. And a major book publishing company hopes to sell at least 5,000 copies of your book. So if you’re writing a book that appeals only to the 44,171 branch managers working at banks nationwide (say, How to Manage Your Branch More Efficiently), and 2% can be persuaded to buy the book, you’ve sold only 883 copies – not nearly enough to make the project worthwhile for either you or a publisher.

2. Is this a book or a magazine article? Will it sell?

There are two substantial differences between a book and a magazine article, which will determine if the material you have will be accepted by a book publisher.

First, there is the matter of time: It can take 18 months to two years from conception to bookstore. If you have an idea for a book about Recession proof Business at the onset of a recession, like I had in 1991, that recession may be over by the time the book comes out and it would not sell. However, a magazine article’s time line of publication (or that of a small booklet) is much quicker (weeks to few months).

Second difference is in length: Do you have enough material for a book?

The average nonfiction book is about 200 pages in published form, with approximately 400 words a page. That’s 80,000 words; about 320 double-spaced typewritten manuscript pages. Most books range between 35,000 words (a slim, 100 pages volume) to 200,000 words or more. An article, on the other hand, can include anywhere from 300 to 2,500 words or so.

How do you know whether your idea is a book, article or booklet – and how do you convince a publishing agent that your concept is a big one? Here are some guidelines:

First, see if there are other books on the topic. The existence of a few similar titles indicates that this idea is big enough to deserve a book.

Second, go to the library and see what else is written on the topic. If you feel overwhelmed by all the magazine articles, newspaper stories, booklets, pamphlets, surveys, reports and statistics on your topic, that’s a good indica­tion the topic is ‘meaty” enough to justify a full-length book.

Third, organize your information into chapters. Think about how you would logically explain your topic or present your information, and organize it into major categories. These will become chapter headings.

A full-length nonfiction book typically has 8-15 chapters. If your outline has fewer, the publisher may think there’s not enough information to fill a book on your topic. Shoot for an outline with at least nine chapters.

A detailed table of contents proves to the book publishing company that your topic is appropriate for a book, not just a magazine article.

3. What’s different or better about your book?

The first page or two of your book proposal must contain an overview of your idea, the book content and its target audience.

The first two paragraphs of your overview must tell the editor why and how your book is unique, different or better than other books already published on this topic.

The angle that makes your book different can take many forms: A slant toward a different audience, a better way of organizing the material, or inclusion of topics not covered in other books.

For instance, my co-author and I wrote a nonfiction book, Technical Writing. Structure, Standards and Style, because we wanted to create a handbook for technical writers that emulated the concise, to-the-point style and format of The Elements of Style, William Strunk and E.B. White’s popular style guide for general writers.

Our proposal called our book “the Strunk and White of technical writing,” which instantly communicated the key appeal of the concept. Our book agent sold the book – within three weeks – to the first book publishing company who looked at it.

Another section of your proposal that positions your book in relation to others on the same subject is the “Competition” section. Here you list and describe competing books; each listing should emphasize how your book is both different and better.

Include in the Competition section those books that cover the same – or very similar – topics as your book; that are published by major publishing houses; and that are no more than five years old.

How many books you list in this section will be important. The presence of two to six competitive books shows there’s a market for this type of book, while still room for one more. On the other hand, if there are seven or more books a publisher may think the field is overcrowded, and you’ll probably have a difficult time making the sale.

4. Will people pay $25.38 for this book?

According to Albert N. Greco, professor of marketing in Fordham University, the average hardcover nonfiction book sells for $25.38; the average trade paperback edition – for $20.40. Your book must be interesting or valuable enough to make readers part not only with their money, but with their time as well.

A how-to or reference book proposal should stress the benefits readers will get when they buy the book. If your book is biography, journalism, history, or any other form of nonfiction written primarily to entertain, your proposal should highlight some of the more fascinating details of the book.

5. Why should the publishing agent hire you to write it?

Your proposal must show why you’re uniquely qualified to write the book. Such qualifications fall into two categories: writing credentials and expert credentials.

Writing credentials establish your expertise as an author. In an “About the Author” section of your book proposal, write a brief biographical sketch of yourself, and include information about your past publications (publishers and dates of publications, excerpts from favorable reviews and sales figures – if they’re impressive).

Expert credentials establish your position as an authority in the topic of your proposed book.

In my experience, your expert credentials don’t need to be in-depth. Editors understand you can research the topic, and they don’t require you to know everything about it before buying your book. They just want to convince their editorial board – and buyers – that you know what you’re talking about.

Of course, having a published book to your credit is one credential that always impresses the book publishing companies. And that’s a credential I’m sure you’ll soon have if you follow the five key points covered in this article.